IMAGING: PET/CT
COMMON QUESTIONS
Q.
How does a PET/CT scan differ from CT or MRI scans?
A.
CT and MRI scans are anatomic imaging modalities, which means that they look at the size and shape of organs and body structures. A PET/CT scan is a metabolic imaging modality, which means it looks at cellular activity. The information collected from a PET/CT scan is different from any other test that is available.
Q.
Is PET/CT scan safe?
A.
The risks associated with a PET/CT scan are very minimal. The quantity of radiation is low and the radiopharmaceutical degrades quickly so that no detectable radioactivity is present after several hours. In addition to the radioactive decomposition, the remaining radiopharmaceutical is eliminated from the body through urine. Family members are not at risk for exposure because approximately 90% of the radioactivity has left the body or decomposed before the patient has left the center.
Q.
Can I have a PET/CT scan if I’m allergic to contrast dyes?
A.
Yes
Q.
What steps do you take to reduce radiation?
A.
We adhere to the As Low As Reasonably Achievable (ALARA) principle, using tools that automatically adjust the radiation dosage based on body type and anatomy. As part of that commitment, we invested in a new technology called iDose that lowers the amount of radiation patients receive by 50% to 70%. The amount of radiation you receive varies by body type and the anatomic region being scanned. Your CT technologist can estimate your radiation dose at the time of your scan. If you had the same CT scan at Oregon Imaging Centers prior to our iDose, your technologist can determine the percentage of radiation reduction.
Q.
Is there an IV involved with the PET/CT?
A.
Yes, please read the “What to Expect” section for details.
Q.
How should I prepare for my CT?
A.
You will receive instructions when you schedule your appointment. You can also refer to the “prep” section of the website. Be sure to review the instructions for your particular study, as they can vary based on type of study.
Q.
Why is there a special diet?
A.
PET/CT scan measures the body’s metabolism. By adhering to the special diet and exercise restrictions we can better measure the metabolic rate of different areas within your body.
Q.
What is a radiopharmaceutical?
A.
A radiopharmaceutical is a radioactive drug. The most commonly used PET/CT radiopharmaceutical is a radioactive form of glucose (sugar). To begin the PET/CT procedure, a small amount of glucose is injected into your bloodstream. There is no danger to you from this injection. Glucose is a common substance that every cell in your body needs in order to function. Diabetic patients do not need to worry; it would take 1,000,000 doses of this radiopharmaceutical to equal the glucose in 1 teaspoon of sugar. Radiopharmaceuticals must pass multiple quality control measures before it is used for any patient injection.
Q.
Are there any potential side effects to a PET/CT scan?
A.
There are no side effects to having a PET/CT scan. Make sure you drink plenty of water and check with your physician if you have any concerns.
Q.
How often should I have a PET/CT scan?
A.
If you are under a physician's care, you should follow your physician's recommendations for frequency of PET/CT scans.
Q.
Why is PET/CT not well known?
A.
PET/CT has been around for years, but originally was used only in research. As the technology grew, PET/CT procedures were performed only in dedicated imaging facilities that had ready access to a cyclotron and a radiochemistry lab to make the radiopharmaceutical. Now, private companies are producing radiopharmaceuticals for distribution to imaging facilities across the country, making it feasible for more medical facilities to offer PET/CT scanning. Oregon Imaging Centers has been performing PET/CT scans in the community for nearly 15 years.
Q.
How many PET studies are performed per year?
A.
Approximately 1.5 to 1.7 million PET/CT scans were performed last year. The number of PET/CT scans performed increases dramatically every year.
Q.
Is a PET/CT scan painless?
A.
The only pain involved is the needle prick when you receive the radiopharmaceutical injection, which does not differ from any other type of injection.